LOCATION AMBRAW IL+IA IN

Established Series
Rev. GOW-RDC-RJB
06/2015

AMBRAW SERIES

The Ambraw series consists of very deep, poorly drained, moderately or moderately slowly permeable soils formed in loamy alluvium. These soils are on flood plains or low terraces of large streams. Slope ranges from 0 to 2 percent. Mean annual air temperature is 54 degrees F., and mean annual precipitation is 40 inches.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Fluvaquentic Endoaquolls

TYPICAL PEDON: Ambraw clay loam - in a cultivated field at an elevation of about 448 feet above MSL. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) clay loam, grayish brown (10YR 5/2) dry; weak medium granular structure; firm; many fine roots; slightly acid; abrupt smooth boundary.

A--8 to 14 inches; very dark gray (10YR 3/1) clay loam, gray (10YR 5/1) dry; weak coarse subangular blocky structure; firm; many fine roots; slightly acid; abrupt smooth boundary. (Combined thickness of the A horizons is 10 to 24 inches.)

Bg1--14 to 18 inches; dark gray (10YR 4/1) clay loam; weak fine and medium subangular blocky structure; firm; many fine roots; common fine distinct brown (10YR 4/3) and dark brown (10YR 3/3) masses of iron and manganese oxides in the matrix; moderately acid; clear smooth boundary.

Bg2--18 to 27 inches; dark gray (10YR 4/1) clay loam; moderate fine and medium prismatic structure parting to weak and moderate medium subangular blocky; firm; common fine and very fine roots; few faint very dark gray (10YR 3/1) organic coatings on faces of peds; few medium rounded black (7.5YR 2.5/1) weakly cemented iron and manganese oxides concretions throughout; common fine faint dark brown (7.5YR 3/2) masses of manganese oxides in the matrix; common fine prominent brown (7.5YR 4/4) masses of iron accumulation in the matrix; moderately acid; gradual smooth boundary.

Bg3--27 to 37 inches; dark gray (N 4/0) clay loam; moderate fine and medium prismatic structure parting to weak medium subangular blocky; firm; few very fine roots; few faint very dark gray (10YR 3/1) organic coatings on faces of peds; common fine and medium prominent brown (10YR 5/3) yellowish brown (10YR 5/8) and strong brown (7.5YR 5/8) masses of iron oxides in the matrix; moderately acid; gradual smooth boundary. (Combined thickness of the Bg horizons is 11 to 49 inches.)

BCg--37 to 45 inches; dark gray (N 4/0) sandy clay loam with thin strata of loam and sandy loam; weak coarse angular blocky structure; firm; many medium prominent dark brown (7.5YR 3/2) masses of manganese oxides in the matrix; many medium prominent strong brown (7.5YR 4/6) masses of iron in the matrix; slightly acid; gradual wavy boundary. (0 to 14 inches thick)

Cg--45 to 60 inches; dark gray (N 4/0) sandy clay loam stratified with pockets and layers of clay loam and silty clay loam; massive; friable; common medium rounded black (7.5YR 2.5/1) weakly cemented iron and manganese oxides concretions throughout; few fine prominent strong brown (7.5YR 5/6) and many medium prominent dark yellowish brown (10YR 3/4) and brown (7.5YR 4/4) masses of iron oxides in the matrix; slightly acid.

TYPE LOCATION: Clark County, Illinois; about 2 miles east of West Union; 2550 feet south and 285 feet east of the northwest corner of sec. 15, T. 9 N., R. 11 W.; USGS West Union, IL topographic quadrangle; lat. 39 degrees, 13 minutes, 23 seconds North, and long. 87 degrees, 37 minutes, 39 seconds West; NAD 27.

RANGE IN CHARACTERISTICS: The depth to the base of soil development is commonly 40 to 50 inches, but ranges to more than 60 inches. The depth to carbonates is greater than 50 inches. The mollic epipedon ranges from 10 to 24 inches in thickness. The particle-size control section averages between 24 and 35 percent clay, 15 and 50 percent fine sand or coarser, and less than 7 percent coarse fragments.

The Ap or A horizon has hue of 10YR, value of 2 or 3 (3 to 5 dry), and chroma of 1 or 2. It is clay loam, silty clay loam, sandy loam, sandy clay loam, or loam. Clay content ranges from 10 to 35 percent and sand content ranges from 5 to 70 percent. It is moderately acid to neutral.

The Bg horizon has properties as follows. The upper part has hue of 10YR or 2.5Y, value of 3 or 4 (5 or 6 dry), and chroma of 1 or 2. It is clay loam, clay, or loam. Clay content ranges from 25 to 42 percent and sand content ranges from 20 to 40 percent. It is strongly acid to neutral.

The lower part of the Bg horizon has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 4 to 6; and chroma of 0 to 2. It is clay loam, loam, or sandy clay loam. Clay content ranges from 24 to 35 percent and sand content ranges from 20 to 60 percent. Volume of coarse fragments is less than 7 percent. It is strongly acid to neutral. Reaction increases as depth increases.

The BCg or Cg horizon has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 4 or 5; and chroma of 0 to 2. It is most commonly clay loam or sandy clay loam, or less commonly sandy loam or loam. Clay content ranges from 18 to 30 percent and sand content ranges from 20 to 60 percent. Volume of coarse fragments is less than 7 percent. The BCg or Cg horizon commonly contains strata. The strata are loam, sandy loam, silt loam, loamy sand, or sand. The BCg horizon is moderately acid to neutral. The Cg horizon is slightly acid to moderately alkaline.

COMPETING SERIES: These are the Gansner, Ozamis, and Sloan series. Gansner soils have a mollic epipedon more than 24 inches thick and do not have a cambic horizon. Ozamis soils do not have a cambic horizon. Sloan soils typically contain carbonates within 50 inches, and average less than 35 percent sand in the particle-size control section.

GEOGRAPHIC SETTING: Ambraw soils are on flood plains or low terraces of large streams. Slope ranges from 0 to 2 percent. They formed in stratified loamy alluvium. Mean annual air temperature ranges from 45 to 57 degrees F., mean annual precipitation ranges from 29 to 45 inches, frost-free period ranges from 140 to 200 days, and elevation ranges from 340 to 1300 feet above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Allison, Beaucoup, Darwin, Gorham, McFain, Riley, Selma, and Titus soils. The well drained Allison soils have less sand in the control section and are on slightly higher topographic positions. Beaucoup soils have less sand in the control section and are on similar positions. Darwin soils contain more clay throughout, have high shrink-swell characteristics, and occupy lower lying slackwater areas further away from main river channels. The poorly drained Gorham soils have less sand in the control section and are on similar positions. McFain soils have more clay in the upper part of the control section, have contrasting particle-size classes, and are in depressions on the flood plain. The somewhat poorly drained Riley soils have contrasting particle-size classes and are on slightly higher parts of the flood plain. Selma soils have less clay and more sand in the lower part of the series control section and are at slightly higher elevations on stream terraces and outwash plains. Titus soils average more than 35 percent clay in the particle-size control section and are in lower lying slackwater areas further from the river channel.

DRAINAGE AND PERMEABILITY: Poorly drained.Permeability is moderate or moderately slow. Where drained, an apparent seasonal high water table is within 1 foot of the surface at some time between January and May in most years. In an undrained condition, the apparent seasonal high water table is within 0.5 foot of the surface at some time between November and June in most years. The potential for surface runoff is negligible to medium. These soils are subject to rare to frequent flooding for brief to long periods between November and June in normal years.

USE AND VEGETATION: The Ambraw soils are used mainly for cultivated crops such as corn and soybeans. A few areas are forested. Native vegetation is probably deciduous forest, sedges, and grasses. See Additional Data section for native vegetative cover in Iowa.

DISTRIBUTION AND EXTENT: Central and southern Illinois, east-central Iowa and Indiana. Series extent is moderate; about 25,000 acres in MLRAs 108A, 113, and 115A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Lawrence County, Illinois, 1952.

REMARKS: A ponded phase and sandy substratum phase are presently recognized. These soils will be evaluated during MLRA updating to determine if new series are needed.

Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - the zone from the surface of the soil to a depth of 14 inches (Ap and A horizons); cambic horizon - the zone from 14 to 45 inches (Bg1, Bg2, Bg3, and BCg horizons);aquic conditions - chroma of 0 or 1 and redoximorphic features in all horizons below the mollic epipedon.

ADDITIONAL DATA: In Iowa, the native vegetative cover is a herbaceous wetland community commonly inhabited with Bluejoint Grasses, Fowl Bluegrasses, Green Muhlies, Fox Sedges, Field Sedges, Dudleys Rushes, Torreys Rushes, Swamp Milkweeds, False Sneezeweeds, False Asters, New England Asters, White Panicled Asters, and Wild Mints. Source: Iowa State Office, Natural Resources Conservation Service, Des Moines, Iowa.

National Cooperative Soil Survey
U.S.A.